The goal of this application is to acquire a new Beckman analytical ultracentrifuge and accessories to be used to establish a facility for the analysis of macromolecules and their interactions between and within macromolecular assemblages are frequently the key to understanding many complex cellular processes of medical importance. A group of 8 investigators with 25 graduate students and 10 post-doctoral fellows will form the initial user group in studies of multi-subunit protein assembly, ligand-dependent self-association processes, other protein-protein interactions, protein-nucleic acid interactions, and micelle-micelle interactions. The facility will become part of an established Protein Microanalysis Core Facility of the Institute for Cellular and Molecular Biology of the University. The ultracentrifuge will be an important tool for research and training of graduate students and postdoctoral fellows in biophysical chemistry.